The Role of the Artery of Ligamentum Teres in Revascularization in Legg-Calve-Perthes Disease

Introduction: A recent cadaveric study supported that most immature hips are supplied by the artery of ligamentum teres and suggested this medial vascular source may influence the pattern of revascularization in Legg-Calve-Perthes disease (LCPD). The purposes of this study were to characterize the perfusion pattern of the capital femoral epiphysis and determine the role of the artery of ligamentum teres in early revascularization of LCPD. Methods: Retrospective review of perfusion magnetic resonance imaging (pMRI) from 64 hips in early stage LCPD (Waldenstrom stage I to IIa) was performed. Two independent graders categorized perfusion pattern based on the presence of perfusion medially (from artery of ligamentum teres) and/or laterally (from the medial femoral circumflex artery) on coronal and sagittal MRI series: type 1-lateral perfusion only, type 2-separate medial and lateral perfusion, or type 3-coalescent medial and lateral perfusion. Lateral pillar classification was obtained for hips that reached mid-fragmentation. Results: We identified 64 patients (75% male) with mean age at diagnosis of 8.5 +/- 2.1 years. 36% (23/64) hips underwent pMRI during stage I and 64% (41/64) during stage IIa. pMRI revealed separate and distinct medial and lateral sources of perfusion (type 2) in 50% (32/64) hips. In stage I, the distribution of type 1/2/3 hips was found to be 26%/52%/22%. However, in stage IIa there was a nonsignificant trend toward greater coalescence of the medial and lateral perfusion with a distribution of type 1/2/3 of 7%/49%/44% (P=0.07). There was a nonsignificant trend toward weak negative linear correlation between lower initial perfusion grade and worsened lateral pillar classification at mid-fragmentation (r=-0.25, P=0.05). Conclusion: The presence of separate and distinct areas of perfusion of medial and lateral capital femoral epiphysis provides further evidence of the role of the ligamentum teres vessels in revascularization during the early stages of LCPD. The changes in perfusion pattern with disease progression likely reflect that medial femoral circumflex artery and ligamentum teres vessel revascularization occur separately, but ultimately coalesce posteriorly over time.

Automated summary

This study found that in early Legg-Calve-Perthes disease, half of the hips showed separate and distinct medial and lateral sources of perfusion. As the disease progressed, there was a trend towards increased coalescence of medial and lateral perfusion. A weak negative correlation was observed between lower initial perfusion grade and worsened lateral pillar classification at mid-fragmentation.